Iris-diaphragm.



A. WOLLENSAK.

IRIS DIAPHRAGM.

APPLIOATION FILED 11:11.27, 1911.

Patented May 23, 1911.

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ANDREW WOLLENSAK, OF ROCHESTER,

FFIGE.

NEW YORK, ASSIGNOR 'IO WOLLENSAK OPTICAL COMPANY, OF ROCHESTER, NEWYORK, A CORPORATION OF NEW YORK.

IRIS-DIAPHRAGM.

Specification of Letters Patent.

Patented May 23, 1911;

Application filed February 27, 1911. Serial No. 611,311.

To all whom it may concern:

Be it known that I, A DREW W OLLENSAK, a citizen of the United States,and resident of Rochester, in the county of Monroe and State of NewYork, have invented certain new and useful Improvements inIris-Diaphragms, of which the following is a specification.

This invention relates to iris-diaphragms such as are employed inconnection with photographic cameras.

The object of the invention is to provide a simple and effective device,to be used in connection with an iris-diaphragm of any ordinary form,for the purpose of frictionally retaining the blade-operating ring ofthe diaphragm in any position to which it may be adjusted, so as toprevent the adjustment of the diaphragm from accidental change throughjarring of the camera or other cause.

To this end the invention consists in the device hereinafter described,as it is defined in the succeeding claims.

In the accompanying drawings: Figure 1 is a rear-elevation, with partsbroken away, of an iris-diaphragm embodying the present invention; Fig.2 is a section on the line 22 in Fig. 1; and Fig. 3 is a sectionaldetail view of the retainer.

The invention is illustrated as embodied in an iris-diaphragmconstructed substantially 'like that described in United States LettersPatent No. 985,311 granted to me February 28, 1911, but it is equallyapplicable to any iris-diaphragm of ordinary form, that is, to anydiaphragm comprising a series of blades and a rotatable ring by justed.

In the drawings the diaphragm is shown as mounted in a shutter-casinghaving a cylindrical body-portion 4 and a rearwardlyprojectingcylindrical portion 12 which is adapted to be screwed into the front ofthe camera in the ordinary manner. The blades 5 of the diaphragm engage,at their ends, two flat rings 6 and 7, the ring 6 being fixed to thecasing by screws 8. The ring 7 is rotatable to adjust the blades in theusual manner, and is provided with an arm or flnger-piece 9 projectingoutside the casing for this purpose.

The novel feature of the diaphragm in which the present inventionresides is a frictional retainer for the blade-ring 7 This retainer isshown in place in Fig. 2 and detached in Fig. 3. It is in the form of asub stantially flat plate 10 of thin resilient sheet-metal. In thedrawings the thickness of this metal is exaggerated, for convenience inillustration, but in practice it may be made of very thin resilientbrass or other metal.

At its outer edge the detent-plate 10 is provided with an annular flange11. which may be formed integral with the plate by a suitable stampingoperation. This flange is of such diameter that when the retainer isforced into the cylindrical portion 12 of the casing the' flange and theplate are held firmly in place by friction. This method of securing theretainer is not only simple and convenient, but it also permitsadjustment of the retainer toward and from the bladering 7. The retaineris so adjusted that it bears against the rear surface of the bladeringwith resilient pressure, thus creating friction between the retainer andthe bladering 7, and also between the two rings 7 and 6. In this mannerthe ring 7 is held with sufficient firmness to prevent its accidentaldisplacement when in use.

The retainer-plate 10 is provided with a central opening in line withthe opening through the diaphragm, and to stiffen the plate at its inneredge it is provided with an annular bead 13 and a forwardly-projectingflange 14. The bead and the flange may be formed by a suitable stampingoperation, and they serve not only to stiffen the plate at its inneredge, but also to give a neat fin- ,ish to the parts, as the flangeoverhangs the which the blades are simultaneously adedge of theblade-ring 7 and serves to conceal the raw edges both of this blade-ringand of the retainer itself.

I claim 1. An iris-diaphragm having, in combination, a cylindricalcasing, a blade-ring rotatable in the casing, and a frictional retainerfor the blade-ring comprising a substantially flat circular resilientplate with a central opening and a peripheral flange, the plate beingheld in yielding frictional engagement with the blade-ring by thefrictional engagement of its peripheral flange with the inner surface ofthe casing.

2. An iris-diaphragm having, in combination, a cylindrical casing, ablade-ring rotatable in the. casing, and a frictional retainer for theblade-ring comprising a sub- With the inner surface of the casing andthe stantlally flat circular reslhent plate wlth a flange at saidopening overlapping the inperlpheral flange and with 21 central openneredge of the blader1ng.

ing bounded by a flange and a head, the ANDREW WOLLENSAK. plate beingheld in yielding frictional en -Witnesses:

gagement With the blade-ring by the fric- D. GURNEE tional engagement ofits peripheral flange L. THON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, 1). G.

